1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */ 2 /************************************************************************** 3 * 4 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA 5 * All Rights Reserved. 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a 8 * copy of this software and associated documentation files (the 9 * "Software"), to deal in the Software without restriction, including 10 * without limitation the rights to use, copy, modify, merge, publish, 11 * distribute, sub license, and/or sell copies of the Software, and to 12 * permit persons to whom the Software is furnished to do so, subject to 13 * the following conditions: 14 * 15 * The above copyright notice and this permission notice (including the 16 * next paragraph) shall be included in all copies or substantial portions 17 * of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 25 * USE OR OTHER DEALINGS IN THE SOFTWARE. 26 * 27 **************************************************************************/ 28 /* 29 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> 30 */ 31 32 #define pr_fmt(fmt) "[TTM] " fmt 33 34 #include <drm/ttm/ttm_bo.h> 35 #include <drm/ttm/ttm_placement.h> 36 #include <drm/ttm/ttm_tt.h> 37 38 #include <drm/drm_drv.h> 39 #include <drm/drm_managed.h> 40 41 static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo, 42 struct vm_fault *vmf) 43 { 44 long err = 0; 45 46 /* 47 * Quick non-stalling check for idle. 48 */ 49 if (dma_resv_test_signaled(bo->base.resv, DMA_RESV_USAGE_KERNEL)) 50 return 0; 51 52 /* 53 * If possible, avoid waiting for GPU with mmap_lock 54 * held. We only do this if the fault allows retry and this 55 * is the first attempt. 56 */ 57 if (fault_flag_allow_retry_first(vmf->flags)) { 58 if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT) 59 return VM_FAULT_RETRY; 60 61 ttm_bo_get(bo); 62 mmap_read_unlock(vmf->vma->vm_mm); 63 (void)dma_resv_wait_timeout(bo->base.resv, 64 DMA_RESV_USAGE_KERNEL, true, 65 MAX_SCHEDULE_TIMEOUT); 66 dma_resv_unlock(bo->base.resv); 67 ttm_bo_put(bo); 68 return VM_FAULT_RETRY; 69 } 70 71 /* 72 * Ordinary wait. 73 */ 74 err = dma_resv_wait_timeout(bo->base.resv, DMA_RESV_USAGE_KERNEL, true, 75 MAX_SCHEDULE_TIMEOUT); 76 if (unlikely(err < 0)) { 77 return (err != -ERESTARTSYS) ? VM_FAULT_SIGBUS : 78 VM_FAULT_NOPAGE; 79 } 80 81 return 0; 82 } 83 84 static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo, 85 unsigned long page_offset) 86 { 87 struct ttm_device *bdev = bo->bdev; 88 89 if (bdev->funcs->io_mem_pfn) 90 return bdev->funcs->io_mem_pfn(bo, page_offset); 91 92 return (bo->resource->bus.offset >> PAGE_SHIFT) + page_offset; 93 } 94 95 /** 96 * ttm_bo_vm_reserve - Reserve a buffer object in a retryable vm callback 97 * @bo: The buffer object 98 * @vmf: The fault structure handed to the callback 99 * 100 * vm callbacks like fault() and *_mkwrite() allow for the mmap_lock to be dropped 101 * during long waits, and after the wait the callback will be restarted. This 102 * is to allow other threads using the same virtual memory space concurrent 103 * access to map(), unmap() completely unrelated buffer objects. TTM buffer 104 * object reservations sometimes wait for GPU and should therefore be 105 * considered long waits. This function reserves the buffer object interruptibly 106 * taking this into account. Starvation is avoided by the vm system not 107 * allowing too many repeated restarts. 108 * This function is intended to be used in customized fault() and _mkwrite() 109 * handlers. 110 * 111 * Return: 112 * 0 on success and the bo was reserved. 113 * VM_FAULT_RETRY if blocking wait. 114 * VM_FAULT_NOPAGE if blocking wait and retrying was not allowed. 115 */ 116 vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo, 117 struct vm_fault *vmf) 118 { 119 /* 120 * Work around locking order reversal in fault / nopfn 121 * between mmap_lock and bo_reserve: Perform a trylock operation 122 * for reserve, and if it fails, retry the fault after waiting 123 * for the buffer to become unreserved. 124 */ 125 if (unlikely(!dma_resv_trylock(bo->base.resv))) { 126 /* 127 * If the fault allows retry and this is the first 128 * fault attempt, we try to release the mmap_lock 129 * before waiting 130 */ 131 if (fault_flag_allow_retry_first(vmf->flags)) { 132 if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { 133 ttm_bo_get(bo); 134 mmap_read_unlock(vmf->vma->vm_mm); 135 if (!dma_resv_lock_interruptible(bo->base.resv, 136 NULL)) 137 dma_resv_unlock(bo->base.resv); 138 ttm_bo_put(bo); 139 } 140 141 return VM_FAULT_RETRY; 142 } 143 144 if (dma_resv_lock_interruptible(bo->base.resv, NULL)) 145 return VM_FAULT_NOPAGE; 146 } 147 148 /* 149 * Refuse to fault imported pages. This should be handled 150 * (if at all) by redirecting mmap to the exporter. 151 */ 152 if (bo->ttm && (bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) { 153 if (!(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE)) { 154 dma_resv_unlock(bo->base.resv); 155 return VM_FAULT_SIGBUS; 156 } 157 } 158 159 return 0; 160 } 161 EXPORT_SYMBOL(ttm_bo_vm_reserve); 162 163 /** 164 * ttm_bo_vm_fault_reserved - TTM fault helper 165 * @vmf: The struct vm_fault given as argument to the fault callback 166 * @prot: The page protection to be used for this memory area. 167 * @num_prefault: Maximum number of prefault pages. The caller may want to 168 * specify this based on madvice settings and the size of the GPU object 169 * backed by the memory. 170 * 171 * This function inserts one or more page table entries pointing to the 172 * memory backing the buffer object, and then returns a return code 173 * instructing the caller to retry the page access. 174 * 175 * Return: 176 * VM_FAULT_NOPAGE on success or pending signal 177 * VM_FAULT_SIGBUS on unspecified error 178 * VM_FAULT_OOM on out-of-memory 179 * VM_FAULT_RETRY if retryable wait 180 */ 181 vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, 182 pgprot_t prot, 183 pgoff_t num_prefault) 184 { 185 struct vm_area_struct *vma = vmf->vma; 186 struct ttm_buffer_object *bo = vma->vm_private_data; 187 struct ttm_device *bdev = bo->bdev; 188 unsigned long page_offset; 189 unsigned long page_last; 190 unsigned long pfn; 191 struct ttm_tt *ttm = NULL; 192 struct page *page; 193 int err; 194 pgoff_t i; 195 vm_fault_t ret = VM_FAULT_NOPAGE; 196 unsigned long address = vmf->address; 197 198 /* 199 * Wait for buffer data in transit, due to a pipelined 200 * move. 201 */ 202 ret = ttm_bo_vm_fault_idle(bo, vmf); 203 if (unlikely(ret != 0)) 204 return ret; 205 206 err = ttm_mem_io_reserve(bdev, bo->resource); 207 if (unlikely(err != 0)) 208 return VM_FAULT_SIGBUS; 209 210 page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) + 211 vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node); 212 page_last = vma_pages(vma) + vma->vm_pgoff - 213 drm_vma_node_start(&bo->base.vma_node); 214 215 if (unlikely(page_offset >= PFN_UP(bo->base.size))) 216 return VM_FAULT_SIGBUS; 217 218 prot = ttm_io_prot(bo, bo->resource, prot); 219 if (!bo->resource->bus.is_iomem) { 220 struct ttm_operation_ctx ctx = { 221 .interruptible = false, 222 .no_wait_gpu = false, 223 .force_alloc = true 224 }; 225 226 ttm = bo->ttm; 227 if (ttm_tt_populate(bdev, bo->ttm, &ctx)) 228 return VM_FAULT_OOM; 229 } else { 230 /* Iomem should not be marked encrypted */ 231 prot = pgprot_decrypted(prot); 232 } 233 234 /* 235 * Speculatively prefault a number of pages. Only error on 236 * first page. 237 */ 238 for (i = 0; i < num_prefault; ++i) { 239 if (bo->resource->bus.is_iomem) { 240 pfn = ttm_bo_io_mem_pfn(bo, page_offset); 241 } else { 242 page = ttm->pages[page_offset]; 243 if (unlikely(!page && i == 0)) { 244 return VM_FAULT_OOM; 245 } else if (unlikely(!page)) { 246 break; 247 } 248 pfn = page_to_pfn(page); 249 } 250 251 /* 252 * Note that the value of @prot at this point may differ from 253 * the value of @vma->vm_page_prot in the caching- and 254 * encryption bits. This is because the exact location of the 255 * data may not be known at mmap() time and may also change 256 * at arbitrary times while the data is mmap'ed. 257 * See vmf_insert_mixed_prot() for a discussion. 258 */ 259 ret = vmf_insert_pfn_prot(vma, address, pfn, prot); 260 261 /* Never error on prefaulted PTEs */ 262 if (unlikely((ret & VM_FAULT_ERROR))) { 263 if (i == 0) 264 return VM_FAULT_NOPAGE; 265 else 266 break; 267 } 268 269 address += PAGE_SIZE; 270 if (unlikely(++page_offset >= page_last)) 271 break; 272 } 273 return ret; 274 } 275 EXPORT_SYMBOL(ttm_bo_vm_fault_reserved); 276 277 static void ttm_bo_release_dummy_page(struct drm_device *dev, void *res) 278 { 279 struct page *dummy_page = (struct page *)res; 280 281 __free_page(dummy_page); 282 } 283 284 vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot) 285 { 286 struct vm_area_struct *vma = vmf->vma; 287 struct ttm_buffer_object *bo = vma->vm_private_data; 288 struct drm_device *ddev = bo->base.dev; 289 vm_fault_t ret = VM_FAULT_NOPAGE; 290 unsigned long address; 291 unsigned long pfn; 292 struct page *page; 293 294 /* Allocate new dummy page to map all the VA range in this VMA to it*/ 295 page = alloc_page(GFP_KERNEL | __GFP_ZERO); 296 if (!page) 297 return VM_FAULT_OOM; 298 299 /* Set the page to be freed using drmm release action */ 300 if (drmm_add_action_or_reset(ddev, ttm_bo_release_dummy_page, page)) 301 return VM_FAULT_OOM; 302 303 pfn = page_to_pfn(page); 304 305 /* Prefault the entire VMA range right away to avoid further faults */ 306 for (address = vma->vm_start; address < vma->vm_end; 307 address += PAGE_SIZE) 308 ret = vmf_insert_pfn_prot(vma, address, pfn, prot); 309 310 return ret; 311 } 312 EXPORT_SYMBOL(ttm_bo_vm_dummy_page); 313 314 vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf) 315 { 316 struct vm_area_struct *vma = vmf->vma; 317 pgprot_t prot; 318 struct ttm_buffer_object *bo = vma->vm_private_data; 319 struct drm_device *ddev = bo->base.dev; 320 vm_fault_t ret; 321 int idx; 322 323 ret = ttm_bo_vm_reserve(bo, vmf); 324 if (ret) 325 return ret; 326 327 prot = vma->vm_page_prot; 328 if (drm_dev_enter(ddev, &idx)) { 329 ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT); 330 drm_dev_exit(idx); 331 } else { 332 ret = ttm_bo_vm_dummy_page(vmf, prot); 333 } 334 if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) 335 return ret; 336 337 dma_resv_unlock(bo->base.resv); 338 339 return ret; 340 } 341 EXPORT_SYMBOL(ttm_bo_vm_fault); 342 343 void ttm_bo_vm_open(struct vm_area_struct *vma) 344 { 345 struct ttm_buffer_object *bo = vma->vm_private_data; 346 347 WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping); 348 349 ttm_bo_get(bo); 350 } 351 EXPORT_SYMBOL(ttm_bo_vm_open); 352 353 void ttm_bo_vm_close(struct vm_area_struct *vma) 354 { 355 struct ttm_buffer_object *bo = vma->vm_private_data; 356 357 ttm_bo_put(bo); 358 vma->vm_private_data = NULL; 359 } 360 EXPORT_SYMBOL(ttm_bo_vm_close); 361 362 static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo, 363 unsigned long offset, 364 uint8_t *buf, int len, int write) 365 { 366 unsigned long page = offset >> PAGE_SHIFT; 367 unsigned long bytes_left = len; 368 int ret; 369 370 /* Copy a page at a time, that way no extra virtual address 371 * mapping is needed 372 */ 373 offset -= page << PAGE_SHIFT; 374 do { 375 unsigned long bytes = min(bytes_left, PAGE_SIZE - offset); 376 struct ttm_bo_kmap_obj map; 377 void *ptr; 378 bool is_iomem; 379 380 ret = ttm_bo_kmap(bo, page, 1, &map); 381 if (ret) 382 return ret; 383 384 ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset; 385 WARN_ON_ONCE(is_iomem); 386 if (write) 387 memcpy(ptr, buf, bytes); 388 else 389 memcpy(buf, ptr, bytes); 390 ttm_bo_kunmap(&map); 391 392 page++; 393 buf += bytes; 394 bytes_left -= bytes; 395 offset = 0; 396 } while (bytes_left); 397 398 return len; 399 } 400 401 int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr, 402 void *buf, int len, int write) 403 { 404 struct ttm_buffer_object *bo = vma->vm_private_data; 405 unsigned long offset = (addr) - vma->vm_start + 406 ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node)) 407 << PAGE_SHIFT); 408 int ret; 409 410 if (len < 1 || (offset + len) > bo->base.size) 411 return -EIO; 412 413 ret = ttm_bo_reserve(bo, true, false, NULL); 414 if (ret) 415 return ret; 416 417 switch (bo->resource->mem_type) { 418 case TTM_PL_SYSTEM: 419 fallthrough; 420 case TTM_PL_TT: 421 ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write); 422 break; 423 default: 424 if (bo->bdev->funcs->access_memory) 425 ret = bo->bdev->funcs->access_memory( 426 bo, offset, buf, len, write); 427 else 428 ret = -EIO; 429 } 430 431 ttm_bo_unreserve(bo); 432 433 return ret; 434 } 435 EXPORT_SYMBOL(ttm_bo_vm_access); 436 437 static const struct vm_operations_struct ttm_bo_vm_ops = { 438 .fault = ttm_bo_vm_fault, 439 .open = ttm_bo_vm_open, 440 .close = ttm_bo_vm_close, 441 .access = ttm_bo_vm_access, 442 }; 443 444 /** 445 * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object. 446 * 447 * @vma: vma as input from the fbdev mmap method. 448 * @bo: The bo backing the address space. 449 * 450 * Maps a buffer object. 451 */ 452 int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo) 453 { 454 /* Enforce no COW since would have really strange behavior with it. */ 455 if (is_cow_mapping(vma->vm_flags)) 456 return -EINVAL; 457 458 ttm_bo_get(bo); 459 460 /* 461 * Drivers may want to override the vm_ops field. Otherwise we 462 * use TTM's default callbacks. 463 */ 464 if (!vma->vm_ops) 465 vma->vm_ops = &ttm_bo_vm_ops; 466 467 /* 468 * Note: We're transferring the bo reference to 469 * vma->vm_private_data here. 470 */ 471 472 vma->vm_private_data = bo; 473 474 vm_flags_set(vma, VM_PFNMAP | VM_IO | VM_DONTEXPAND | VM_DONTDUMP); 475 return 0; 476 } 477 EXPORT_SYMBOL(ttm_bo_mmap_obj); 478